In wiper apparatus for vehicles, an arm shank is pivotably supported at its proximal end portion on a vehicle body, an arm piece is mounted to a distal end portion of the arm shank, and a wiper blade is mounted to the arm piece. Window glass is wiped with the wiper blade through pivoting movement of the ark shank.
Generally, such wiper apparatus are mounted on a vehicle body with the arm piece swaged to a distal end portion of the arm shank. Therefore, a step or level difference would be formed between the distal end portion of the arm shank and the arm piece, which impairs the outer appearance of the wiper apparatus.
To eliminate such an undesired level difference between the distal end portion of the arm shank and the arm piece, it has been proposed to form a sectional shape of the arm piece such that a portion of the arm shank to be swaged to the distal end portion of the arm shank has a relatively small size and another portion of the arm shank projecting from the distal end portion of the arm shank has a greater size (see, for example, the wiper apparatus disclosed in Japanese Patent Application Laid-Open Publication No. 2000-344057). By thus appropriately changing the sectional shape of the arm piece, it is possible to minimize or eliminate the level difference between the distal end portion of the arm shank and the arm piece; in this way, the outer peripheral surface of the arm piece can be made flush with the outer peripheral surface of the arm shank.
However, with the wiper apparatus disclosed in the 2000-344057 publication, which requires a particular sectional shape of the arm piece, it is difficult to appropriately shape the arm piece. Thus, formation of the arm piece tends to be complicated. Therefore, it has also been proposed to form the arm piece of resin so that it can be readily molded into the particular sectional shape. If the arm piece is formed of resin like this, however, a sufficient rigidity of the arm piece can not be secured, and as a consequence, the arm piece can not appropriately press the wiper blade against a window glass. Therefore, the window glass can not be appropriately wiped with the wiper blade of the wiper apparatus.